The invention relates to dental compositions and methods of use thereof to bind hard tooth, metal and ceramic. The invention provides compositions including complexes formed by reacting multivalent cation with acid moieties of ethylenically unsaturated Monomers and prepolymers. The invention provides compositions with superior adhesion to dentin, enamel and cementum without the need for separate steps of acid etching dental enamel to adhere thereto. Compositions of the invention are useful as dental luting cements, liners, bases and restoratives. The compositions of the invention are hydrolytically stable. The heterogeneous multi-phase dental compositions of the invention show improved mechanical strength, for example, improved bond strength to tooth and are less sensitive to the effects of moisture.
Glass ionomers are described by A. Wilson in U.S. Pat. Nos. 5,079,277 and 4,758,612. Prior art glass ionomer compositions are combinations of a polyalkenoic acid polymer such as polyacrylic acid and an elutable glass which provides a source of cations to react with the polyacrylic acid. Prior art glass ionomers are brittle and weak in high stress applications and set poorly in the presence of moisture unless protected from water. Prior art pit and fissure materials include polymerizable hydrophobic resins with essentially no adhesion to tooth. They are adhered by infiltrating micromechanical undercuts produced by acid etching. They harden in-situ to protect the tooth from colonization by bacteria in order to reduce caries, but because they are difficult to use they are not universally employed to achieve this valuable result. They require the tooth be cleaned, acid etched, washed, dried and isolated by rubber dam to maintain dryness, to avoid contamination by saliva, and achieve suitable results. The procedure is thus uncomfortable for the patient and laborious for the dentist. The present invention provides pit and fissure sealant compositions which are applied to tooth without a separate acid etching step.
Olivier in U.S. Pat. No. 3,234,181 discloses melt-fabricable end-capped aromatic polyimides.
Lonerini in U.S. Pat. No. 3,407,176 discloses polyamide-acids and polymide from a mixture of dianhydrides.
Gall in U.S. Pat. No. 3,422,061 discloses coalesceable polyimide powders from a polycarboxylic aromatic dianhydride and phenylene diamine.
Angelo in U.S. Pat. No. 3,424,718 discloses copolymers of aromatic tetracarboxylic acids with at least two organic diamines.
Rogers in U.S. Pat. No. 3,959,350 discloses melt-fusible linear polyimide of 2,2-bis(3,4-dicarboxyphenyl)-hexafluoropropane dianhydride.
Madsen in U.S. Pat. No. 4,322,207 discloses dental cleaning slurry.
Beede et al in U.S. Pat. No. 4,324,591 discloses modifying agents for ion-leachable cement compositions.
Gibbs in U.S. Pat. No. 4,336,175 discloses polymide precursor solutions.
Schmitt et al in U.S. Pat. No. 4,372,836 disclose light curable acrylic dental composition with calcium fluoride pigment.
Smyth in U.S. Pat. No. 4,401,773 discloses highly reactive ion-leachable glass.
Denyer et al in U.S. Pat. No. 4,457,818 discloses dental compositions from urethane acrylate, diacrylate monomer, camphorquinone and dimethylaminoethyl methacrylate.
Ratcliffe et al in U.S. Pat. No. 4,459,193 discloses dental compositions containing camphorquinone and organic peroxide as catalyst.
Denton, Jr. et al in U.S. Pat. No. 4,492,777 discloses heat treated barium or strontium glass.
Bowen in U.S. Pat. No. 4,514,527 discloses method for obtaining strong adhesive bonding of composites to dentin enamel and other substrates.
Bowen in U.S. Pat. No. 4,521,550 discloses method for obtaining strong adhesive bonding of composites to dentin, enamel and other substrates.
Martin in U.S. Pat. No. 4,525,256 discloses photopolymerizable composition including catalyst comprising diketone plus 4-(N,N-Dimethylamino)benzoic acid or ester thereof.
Bowen in U.S. Pat. No. 4,588,756 discloses multi-step method for obtaining strong adhesive bonding of composites to dentin, enamel and other substrates.
Ratcliffe et al in U.S. Pat. No. 4,602,076 discloses photopolymerizable compositions.
Peters in U.S. Pat. No. 4,612,361 discloses poly(etherimides) and compositions containing the same.
Blackwell et al in U.S. Pat. No. 4,657,941 discloses biologically compatible adhesive containing a phosphorus adhesion promoter and a sulfinic accelerator.
Bowen in U.S. Pat. No. 4,659,751 discloses simplified method for obtained strong adhesive bonding of composites to dentin, enamel and other substrates.
Gallagher et al in U.S. Pat. No. 4,680,373 discloses process for the production of a random copolymer containing repeating polyimide units and repeating polyetherimide units.
Aasen et al in U.S. Pat. No. 4,719,149 discloses method for priming hard tissue.
Berdahl et al in U.S. Pat. No. 4,794,157 discloses polyetherimide copolymers, and method for making.
Engelbrecht et al in U.S. Pat. No. 4,806,381 discloses polymerizable compounds containing acid and acid derivatives, mixtures containing the same, and use thereof.
Blackwell et al in U.S. Pat. No. 4,816,495 discloses biologically compatible adhesive visible light curable compositions.
Calla et al in U.S. Pat. No. 4,864,015 discloses method for making thianthrene dianhydride and polyimides obtained therefrom.
Engelbrecht in U.S. Pat. No. 4,872,936 teaches dental cement mixtures containing polymerizable unsaturated monomers and/or oligomers and/or prepolymers containing acid groups and/or their reactive acid-derivative groups.
Aasen et al in U.S. Pat. No. 4,880,660 discloses method for priming hard tissue.
Kawaguchi et al in U.S. Pat. No. 4,918,136 discloses adhesive composition.
Ibsen et al in U.S. Pat. No. 4,964,911 discloses adhesive bonding of acrylic resins, especially in dentistry.
Huang et al in U.S. Pat. No. 4,966,934 discloses biological compatible adhesive containing a phosphorous adhesion promoter and accelerator.
Hirasawa et al in U.S. Pat. No. 4,985,198 discloses tooth-adhesive compounds.
Okada et al in U.S. Pat. No. 5,055,497 discloses curable resinous composition.
Akahane et al in U.S. Pat. No. 5,063,257 discloses dental glass ionomer cement compositions.
Wilson et al in U.S. Pat. No. 5,079,277 discloses polyvinylphosphonic acid and metal oxide or cermet or glass ionomer cement.
Mitra in U.S. Pat. No. 5,130,347 discloses photocurable ionomer cement systems.
Mitra et al in U.S. Pat. No. 5,154,762 discloses universal water-based medical and dental cement.
Ohno et al in U.S. Pat. No. 5,171,763 discloses curable composition.
Rambosek in Canadian Patent 873,935 discloses lithium aluminum silicate, polymer dental filling compositions.
Rossi in Canadian Patent 934,085 discloses dental restorative material of improved polishability.
Spoor in Canadian Patent 968,741 discloses production of coatings by curing with ionizing radiation.
Knight in Canadian Patent 969,299 discloses resins prepared from vinyl-ended polyurethane prepolymers.
Wailer in Canadian Patent 983,190 discloses photopolymerizable acrylic dental products.
Lee et al in Canadian Patent 1,018,294 discloses dental filling package.
O""Sullivan in Canadian Patent 1,020,687 discloses urethaneacrylate dental filling composition.
Rockett et al in Canadian Patent 1,028,441 discloses three package dental restoration system.
Lorenz in Canadian Patent 1,117,242 discloses coating composition comprising N-vinyl-2-Pyrrolidone and an oligomer.
Osborn in Canadian Patent 1,131,388 discloses radiation curable urethane compositions.
Davies et al in Canadian Patent 1,136,796 discloses potopolymerizable compositions.
Skudelny et al in Canadian Patent 1,154,895 discloses flowable mixture and use of synthetic calcium silicate.
Schaefer in Canadian Patent 1,159,984 discloses dental material having a plastics material base.
Munk in Canadian Patent 1,164,124 discloses pourable solid mixture.
Chevreux et al in Canadian Patent 1,176,787 discloses photosetting adhesive composition.
Gruber et al in Canadian Patent 1,179,094 discloses radiation curable coating composition comprising an oligomer and a copolymerizable ultra-violet absorber.
Morgan in Canadian Patent 1,194,637 discloses UV and thermally curable, thermoplastic-containing compositions.
Ratcliffe et al in Canadian Patent 1,198,847 discloses dental Compositions.
Szycher et al in Canadian Patent 1,200,647 discloses actinic radiation cured polyurethane acrylic copolymer.
Temin et al in Canadian Patent 1,213,699 discloses dental restorative composition.
Moran in Canadian Patent 1,216,982 discloses cure to elastomers composition
Ibsen et al in Canadian Patent 1,243,796 discloses dental composite and porcelain repair.
Ibsen in Canadian Patent 1,244,177 discloses methacrylate functional resin dental composite and porcelain repair compositions.
Ying in Canadian Patent 1,259,149 discloses dental restorative composition containing monofunctional monomer.
Randklev in Canadian Patent 1,261,992 discloses orthodontic bracket adhesive compositions.
Waknine in Canadian Patent 1,262,791 discloses a two component (Paste-Paste) self curing dental restorative.
Dougherty et al in Canadian Patent 1,262,981 discloses methods for posterior dental restoration employing light curable packable compositions.
Waknine in Canadian Patent 1,269,790 discloses dental restorative material.
Heid et al in Canadian Patent Application 2,009,471 discloses Hybrid plastic filling material.
Ibsen et al in Canadian Patent Application 2,011,438 discloses light-curable ionomer dental cement.
Rheinberger et al in Canadian Patent Application 2,038,695 discloses polymerizable dental materials.
Rheinberger et al in Canadian Patent Application 2,051,333 discloses polymerizable dental material.
Billington in European Patent Application 0 241 277 discloses glasses and poly(carboxylic acid) cement compositions containing them.
Billington in European Patent Application 0 244 959 discloses glass/poly(carboxylic acid) cement compositions.
Montgomery in European Patent Application 0 325 038 discloses surface priming composition for proteinaceous substrates, method of making and using same.
Kawaguchi et al in European Patent Application 0 335 645 discloses adhesive composition.
Griffin et al in European Patent Application 0 470 446 A1 discloses High glass transition temperature mixed polyimides and composites formed therefrom.
Masuhara in U.K. Patent Application 2 000 789 A discloses curable composition.
Hirasawa in U.K. Patent Application 2 156 347 a discloses (Meth) acrylic acid ester compounds boundable to tooth substrates.
Akahane et al U.K. Patent Application 2 202 221 discloses glass powders for dental glass ionomer cements.
U.S. Pat. No. 4,588,756 relates to aromatic based compositions employed in dentistry as a component in a dental adhesive system requiring multiple pretreatment steps including application of an acid.
Engelbrecht in U.S. Pat. No. 4,872,936 broadly teaches dental cement mixtures containing polymerizable unsaturated monomers and/or oligomers and/or prepolymers containing acid groups and/or their reactive acid-derivative groups.
Mitra in U.S. Pat. No. 5,130,347 discloses a photocurable ionomer cement having a photocurable amid monomer.
Mitra in U.S. Pat. No. 5,154,762 discloses water soluble reducing and oxidizing agents.
It is an object of the invention is to provide new dental compositions useful as filling materials, cavity liners and bases, cements, and pit and fissure sealants other restorative materials which are adhesive to tooth structure.
It is an object of the invention to provide a composition which reduces the steps and time required to adhere metal or ceramic to tooth structure.
It is an object of the invention to provide an adhesive composition for adhesion between tooth structure and/or bone and polymeric composites.
It is an object of the invention to provide dental compositions that are relatively inexpensive and easy to manufacture.
xe2x80x9cMonomerxe2x80x9d as used herein means monomer or oligomer.
xe2x80x9cSetxe2x80x9d as used herein means a polymerizable composition undergoes a change so that it becomes firm, stiff and nonpliable.
As used herein xe2x80x9cThe MAX Litexe2x80x9d means THE MAX(trademark), a curing unit for light-polymerizable dental materials sold by Dentsply International Inc. through its L. D. Caulk Division.
Throughout this disclosure unless otherwise specified amounts of each component of a composition are in percent by weight.
The invention provides dental compositions and methods of using them for adhering to hard tooth structures, metal and ceramic. The compositions include shelf stable complexes of ethylenically unsaturated monomers reacted with cations. These compositions have superior adhesion to tooth without separately acid etching dentin or enamel. Compositions of the invention are useful as dental luting cements, liners, bases and restoratives pit and fissue sealants. In accordance with a method of polymerization of the invention is provided the sequence of steps of forming a substantially pliable polymerizable composition, including polymerizable complex coated particles within the scope of the general formula: 
wherein each Moiety independently is a moiety having at least one acid group and at least one polymerizable group each M is a multivalent cation of Particle which forms a complex by bonding to one or more Moiety, and t, r and q each independently is a number having an average value of 1 or more, storing the polymerizable composition for at least 12 hours, and applying the polymerizable composition to a tooth.
Compositions of the invention provide superior adhesion to dentin, enamel and bone. In a preferred embodiment compositions of this invention are used without a separate step of etching the surfaces to be joined. The adhesive dental materials provided by this invention include restorative materials especially cavity bases and liners, luting cements, pit and fissure sealants and filling materials.
In accordance with the invention is provided a method of polymerizing polymerizable composition which includes a polymerizable salt (complex) within the scope of the general formula (A1) and/or a novel material within the scope of general formula (A1xe2x80x2): 
wherein each Moiety independently is a moiety having at least one acid group and at least one polymerizable group, each M is a multivalent cation which forms a complex by bonding to one or more Moieties; Particle is a particle, r, t, and q each individually is a number having an average value of 1 or more. In general formula A1xe2x80x2 M is a cation of Particle. Preferably, the Particle is glass or ionomeric polymer. The composition is stable and adapted to not set in order of increasing preference for at least 12 hours, 24 hours, or 36 hours, more preferably for at least 7 days and most preferably for at least 1 year in the absence of polymerization initiation. The letter is preferably greater than 100, more preferably greater than 1,000 and most preferably greater than 10,000. A composition in accordance with a preferred embodiment of the invention includes a substantial portion of polymerizable salt within the scope of general formula A1 in equilibrium with polymerizable acid(s) and a source of multivalent cation(s). The polymerizable salt in such compositions is preferably formed by mixing a polymerizable acid and a source of multivalent cations in the presence of water. The polymerizable salt is preferably in equilibrium with the polymerizable acid and a source of multivalent cations for extended periods of time, for example, more than one year. These compositions do not require hermetic sealing to prevent substantial setting as is required by prior art compositions. Thus, these compositions advantageously form, for example, one component compositions which do not substantially set, and are thus, shelf stable preferably for more than one year. It is preferred that the salt forms on the outer surface, perferably as a coating on glass particles used as multivalent cation sources, and that upon polymerization of the polymerizable group a stronger material is formed than in prior art compositions which are multicomponent systems and/or do not include water as a component of the composition applied to a tooth. Preferably these compositions are mixed with Monomers and/or prepolymers and applied to a tooth. These compositions preferably include at least one Monomer and/or polymers which does not include an acid moiety.
More specifically the invention provides a polymerizable composition which includes a polymerizable salt (complex) within the scope of the general formula (B1) and/or a novel material within the scope of the general formula (B1xe2x80x2): 
wherein each Group independently is a polymerizable group, each A independently is an acid group, each Divalent independently is a divalent organic moiety, each M independently is a multivalent cation which forms a complex by bonding to one or more A; Particle is a particle and o, p, q, r, s and t each independently is a number having an average value of at least 1. Preferably M is a multivalent ion of a glass particle. This composition is adapted to not set for at least 24 hours in the absence of polymerization initiation.
Preferably polymerizable compositions in accordance with the invention include at least 1 percent by weight, more preferably at least 3 precent by weight of polymerizable complexes within the scope of general formula (A1).
Complexes within the scope of general formulas, A1 and B1, preferably have molecular weights less than 100,000; more preferably less than 20,000 and most preferably less than 5,000 and especially preferred are such complexes having molecular weights less than 1,000.
Particulate material within the scope of general formulas A1xe2x80x2 and B1xe2x80x2 preferably have a particle size having a longest dimension in order of increasing preference of: less than 1 mm, less than 0.1 mm, less than 0.01 mm or less than 0.001 mm.
Dental compositions of the invention include polymerizable unsaturated substituted aromatic complexes within the scope of the general formula (I): 
wherein X is 
wherein
R1 and R2 each independently is a polymerizable unsaturated moiety having from 2 to 13 carbon atoms,
R3, R4, R5, and R6 each independently is hydrogen, halogen, alkyl having from 1 to 10 carbon atoms or halogenated alkyl of from 1 to 10 carbon atoms,
R9, R10, R11, R12, R13 and R14 each independently is hydrogen, alkyl having from 1 to 10 carbon atoms or aryl having from 6 to 10 carbon atoms,
Z1 and Z2 each independently is a moiety including an acid group,
a, m and n each independently is 0 or 1,
b, and p independently is an integer from 1 to 10, l is from 1 to 3, and
M is a multivalent cation which reacts with acid moieties to form a complex.
In accordance with a preferred embodiment of the invention R1 and R2 each independently is: 
wherein
R7 a divalent carbon containing radical and
R8 is hydrogen, halogen or alkyl having from 1 to 10 carbon atoms.
In a preferred embodiment of the invention compounds are provided within the scope of general formula I wherein n and m are zero, X is oxygen, sulfonyl or ditrifluoromethyl; and R1 and R2 are 
Most preferably compounds within the scope of general formula I are those wherein X is oxygen or ditrifluoromethyl, and M is barium, calcium, strontium or aluminium. Preferred polymerizable unsaturated groups R1 and R2 independently are alkenyl, alkenoxy, cycloalkenyl, arylalkenyl, and alkenaryl moieties; with vinyl, and styryle moieties being more preferred, and acryl and methacryl moieties that constitute the polymerizable groups of many monomers in dental materials being especially preferred.
Exemplary R1 and R2(meth)acrylate moieties include: 
where n preferably is an integer from 1 to 10. Preferably R1 and R2 are (meth)acryloyloxyethyl moieties.
Preferred compounds for use in complexes within the scope of formula I include diesters which are the adducts of 2,2-bis(3,4-dicarboxylphenyl)hexafluoropropane anhydride, 4,4xe2x80x2-oxydiphthalic anhydride, 4,4xe2x80x2-sulfonyldiphthalic anhydride, respectively with 2-hydroxyethyl methacrylate. In a preferred embodiment at least two aromatic rings of a compound for use in complexes with the scope of formula I are joined through at least one saturated carbon, oxygen or sulfonyl.
Aromatic dianhydrides preferred for making compounds for use in complexes within the scope of general formula I react to form partial esters and carboxylic acid functionality. Dianhydrides having at least two aromatic rings are more preferred. Most preferably at least two aromatic rings are joined as shown in formula I to provide disruption of conjugation between the aromatic rings. It has been found that such compositions are less sensitive to light induced changes in color, and are therefore preferred when esthetic considerations are of importance. Most preferred examples are 4,4xe2x80x2-oxydiphthalic anhydride and 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride.
Dental compositions in accordance with a preferred embodiment of the invention include an acid functional polymerizable organic ester for use in complexes within the scope of general formula I, water, cation elutable glass filler, and a polymerization catalyst system. Optionally, additional polymerizable monomers and/or prepolymers are included.
A composition in accordance with a preferred embodiment of the invention provides polymerizable monomer having at least one acid radical or reactive acid derivative, and a source of cations reactive with the acid moiety, and a catalyst system. Preferably the catalyst system promotes free radical polymerization and preferably includes visible light curing and/or a redox catalyst system. Preferably the composition includes liquid diluents, and/or filler adjuvants. Diluent preferably co-polymerizes with the polymerizable monomer within the scope of general formula A1. Alternatively the diluent is nonreactive with the polymerizable monomer. Water or low boiling alcohols such as methanol, ethanol, and isopropanol are nonreactive diluents. Suitable polymerizable co-monomers are disclosed in U.S. Pat. No. 4,657,941 particularly at column 3 line 5 through column 5 line 59 and U.S. Pat. No. 4,514,342 both of which are incorporated herein by reference. The filler adjuvants are preferably reactive, for example by providing a source of cations which are reactive with the acid moiety of the polymerizable monomer. Nonreactive filler is preferably included in compositions in accordance with a preferred embodiment of the invention. Optionally, fillers have surface treatments to improve compatibility and strength of the resulting composition. Exemplary fillers include silica, silicates, alumina, aluminates, calcium fluoride, strontium fluoride, glasses including fluorine glasses, ceramics and minerals including mica, zeolites, ceramics, calcium apatites and organic polymers and those disclosed in U.S. Pat. Nos. 4,758,612 and 5,079,277.
A preferred composition of the invention includes a monomer compound for use in complexes within the scope of general formula A1, at least one finely divided reactive filler which provides a source of cations reactive with the acids or acid derivative of the monomer compound and curing agent. A dental composition in accordance with the invention includes a compound for use in complexes of general formula A1, catalysts, initiators, accelerators, filler, adjuvants, source of cations, water, and diluent. Dental cements and dental filling compositions in accordance with a preferred embodiment of the invention include monomer compounds for use in complexes within the scope of general formula A1.
The compounds for use in complexes within the scope of general formula A1 have at least two different functional substituent groups, one of which is capable of addition polymerization and the other of which is carboxyl or other acid or reactive acid derivative. Most preferably these compounds include at least one polymerizable group and one or more acid or reactive acid derivative groups. Preferred compounds within the scope of general formula A1 are derived acid formed from the reaction of 4,4xe2x80x2-oxydiphthalic anhydride or 2,2-bis(3,4-dicarboxylphenyl)hexafluorpropane dianhydrides with a polymerizable hydroxyl or polyhydric compound to form esters and partial esters thereof.
The new salt compounds of the invention are capable of being polymerized to form linear or crosslinked polymers which contain multiple acid groups or reactive acid derivative groups that have been reacted with cations, especially those of valence 2 or greater to form poly-salts. Because the salt compounds are monomers of relatively low molecular weight with a high density of both ethylenic unsaturation and carboxylic reactive acid derivative sites, excellent curing with superior integrity occurs. The carboxyl group itself is most preferred over other acid moieties or the reactive acid derivative ions. Especially appropriate acid moieties are all those that react with oxidic, mineral, ceramic, vitreous, or metallic fillers. Examples of these other acid moieties include: 
of phosphorus acids wherein R is alkyl, aryl, or vinyl; the moieties xe2x80x94SO2H, SO3H, or xe2x80x94Oxe2x80x94SO3H of sulfuric acids; the moieties: 
of boron acids wherein R is alkyl, aryl, or vinyl and cationic acid moieties including xe2x80x94NR2H+ wherein R is H or alkyl. The reactive acid derivatives can be substituted with acid halides, with acid anhydrides, and with acid amides, nitrites, and esters that readily hydrolyze into acid, such as can enter into ion-exchange, neutralization, salt formation, or chelation reactions with the reactive filler. Preferred acid or reactive acid derivatives are carboxylate, phosphate, phosphonate, sulfonate, or borate acid moieties and/or of their reactive derivatives.
The compositions of the invention are formulated as one, two or more components, visible light curable, self cure, and/or dual cure product or combinations of these. The composition of a preferred embodiment of the invention includes polymerizable carboxylic acid monomer, an optional filler and/or diluent, a cationic elutable glass or other source of polyvalent cations, and a polymerization catalyst system. The polymerizable carboxylic acid monomers are chosen to provide a suitable balance of hydrophobic and hydrophilic moieties in order to provide a balanced set of properties including adhesion to metal, ceramics and tooth. They are essentially non-volatile and not critically affected by moisture during hardening within the oral cavity; and provide the ability to be used on hydrated surfaces such as found on and in teeth; and in a preferred embodiment do not require the separate steps of acid etching and adhesive priming to achieve adhesion to tooth structure.
For a better understanding of the characteristics and method of producing the preferred ethylenically unsaturated carboxylic compounds for use in complexes of the present invention the preparation of a preferred series of the compounds is carried out as follows:
In the presence of acid, base or other suitable catalyst one mole 4,4xe2x80x2-oxydiphthalic anhydride is reacted with two moles of a compound of the general formula Rxe2x80x94OH, wherein R is a polymerizable unsaturated moiety having from 2 to 13 carbon atoms. This yields a liquid product which is believed to be a mixture of isomer monomers of general formulas II-IV: 
As discussed in detail in Example 3 by reacting one mole of oxydiphthalic anhydride with two moles of methacryloyloxyethyl alcohol also known as 2-hydroxyethyl methacrylate (HEMA) in the presence of catalyst a liquid product is formed which is believed to be a mixture of isomer monomers V-VII: 
Monomer compounds for use in complexes within the scope of general formula I are reactive esters which have at least one unreacted carboxylic acid group and one polymerizable group in the monomer. The number of reacted or unreacted carboxylic acid groups in the monomer is controlled by varying the reaction conditions and molar ratio of reactants. The monomer compounds of the invention polymerize by addition polymerization through the ethylenically unsaturated group. Curing agents, catalysts, initiators and/or accelerators, are used to expedite and control the polymerization. A peroxide initiator, for example benzoyl peroxide, and/or heat are useful to initiate the reaction. Accelerators enhance the reaction so that it may proceed more expeditiously at room temperature. Accelerators preferably include reducing agents such as amines or sulfinates, and/or transition metal ions. Ultraviolet and/or visible light are used with initiators and accelerators to initiate and accelerate the polymerization. Visible light curing is preferred for curing the compositions of the invention in the mouth. For preformed objects, or those cured outside the body, other forms of radiation, for example ultraviolet ionizing radiation is preferred for curing the compositions of the invention.
In accordance with the method of the invention in-vivo polymerization does not harm the patient within whom polymerization of monomer compound (or complexes) within the scope of general formula I occurs. Preferably a single part composition is induced to polymerize by the application of heat or light. To initiate by irradiation with ultraviolet or visible light the initiator, for example a benzophenone or camphorquinone is preferably used to form a single, premixed, ready to use shelf-stable composition. A preferred embodiment of the composition of the invention includes a polymerization catalyst system having a light sensitive polymerization initiator such as camphorquinone, a reducing agent such as ethyl 4-dimethylaminobenzoate (EDAB) and an oxidizing agent such as benzoyl peroxide. Redox polymerization systems known to the art are preferably used to polymerize the composition of the invention. Preferred redox polymerization catalyst systems for use in accordance with the invention include, a peroxide and tributyl boron and/or a transition metal salt. Redox polymerization catalysts and catalyst systems are those disclosed in U.S. Pat. No. 4,657,941 at column 7 line 10 through column 8 line 27 incorporated herein by reference. A particular polymerization method and system may be preferred depending on the application requirements of the material. Whatever the mode of polymerization, or xe2x80x9cset or curexe2x80x9d of the composition including the salt monomers, an important characteristic of the polymers which form is that they have been prereacted with di- or polyvalent cations. The salt compounds and compositions of the invention exhibit adhesion between the resin and a cation containing surface, metal, metal oxide, tooth, and/or bone against which they are polymerized.
Fillers which are especially suited for use in compositions of the invention are inorganic glasses such as are used in glass ionomer cements. Exemplary of such fillers are those of U.S. Pat. No. 4,814,362 which is incorporated herein by reference in its entirety. Preferred fillers are glasses formed from or including, barium, calcium, strontium, lanthanum, tantalum, and/or tungsten silicates and aluminates and/or aluminosilicates, silica, including submicron silica, quartz, and/or ceramics for example, calcium hydroxy apatite. In a preferred embodiment of the invention reactive cations, especially those of calcium, strontium and aluminum, and anions especially fluoride ions; are eluted from the fillers. The fillers used in the invention preferably are reduced in particle size and in a preferred embodiment are silanated before they are incorporated into such compositions. Preferred levels of filler are from about 20% to about 85% based on the total weight of the cement composition, with from about 40% to about 85% being more preferable and about 50-80% being most preferred. If a more finely particulated filler is used, amounts of filler may be decreased due to the relative increase in surface area which attends the smaller sizes of particles. Preferred particle size distributions are from 0.02 to 50 microns, more preferably 0.1 to 10 microns, and most preferably 1 to 6 microns.
In a preferred embodiment of the invention the cations of the salts are di- and polyvalent cations, such as Sr, Ca, Al and Ba. In another preferred embodiment compositions of the invention include solvents, plasticizers, pigments, anti-microbials and therapeutics which may be time released from the composition, and oxidation inhibitors such as butylated hydroxytoluene. In addition to compounds within the scope of general formula I compositions in accordance with the invention preferably include polymerizable unsaturated diluent monomers, oligomers and/or prepolymers that do not contain any acid groups and/or salts thereof and/or reactive readily hydrolyzing acid-derivative groups thereof. One such preferred monomer is hydroxyalkyl methacrylates. Compositions of the invention may also preferably include compounds having acid groups and/or their salts and/or their readily reactive hydrolyzing derivative groups but do not contain any groups that are unsaturated and polymerizable, such as multi-basic acids or their reactive, readily hydrolyzing derivatives. Especially preferred multibasic acids are hydroxy acids such as tartaric or citric acid.
Compounds that have chelating groups but do not contain carboxylic acid groups or readily hydrolyzing acid-derivative groups are preferably included in composition in accordance with the invention, for example vanillates, syringates, and salicylates.
Mixing the compositions of the present invention may be achieved using standard compounding techniques. For example, liquids, photoinitiator(s), and accelerator(s) are blended first, and fillers are added incrementally thereafter. When blending light sensitive compositions, however, a photosafe room illumination, i.e., one that does not contain substantial amounts of wavelengths of electromagnetic radiation that would activate the photoinitiating system is used to avoid initiating polymerization of the composition prematurely.
Cements
The salt compounds of compositions of the present invention also have medical applications such as in self adhesive bone cements. However, they are most preferred to use in dental treatment by application to a tooth or a number of teeth in vivo, in the mouth of a live patient by a dentist or dental practitioner.
The application of the compositions of the invention is preferably as a dental cement applied to tooth. The dental cement compositions of the invention preferably include a salt compound within the scope of general formula I, and other ingredients, such as curing catalysts, initiators, accelerators, diluents and/or adjuvants. The composition is applied as a cement using conventional techniques and preferably cured with application of visible light in a conventional manner. Cements in accordance with the invention are self adhesive to dentin and enamel. These cements are used in bonding dentin to structures, for example, to bond a ceramic inlay to a prepared cavity of a tooth. Inlays preferably are polymers, or ceramics which are cast or built-up from porcelain frits and fired. Alternatively, inlays are machined from metal such as titanium or gold or preformed polymeric composite or homogeneous monolithic polymer compositions, for example by CAD-CAM procedures. In accordance with a preferred embodiment of the invention metal or ceramic superstructures for crowns, and bridges and/or orthodontic appliances are bonded to teeth using cement compositions of the invention. Such cement compositions join metal or ceramic to tooth by application of the cement composition by bringing them into contact until the cement hardens.
A preferred composition of the invention includes a two-part system. One part includes a curing agent. The two parts are spatuled to form a cement prior to placement on tooth. The placement is by standard technique(s). Preferably the cement includes a visible light and/or a self-curing redox polymerization initiator system. In a preferred embodiment of the invention luting cement compositions have low viscosity and film thicknesses less than about 25 xcexcm to bond close fitting appliances to prepared teeth. In one embodiment luting cement compositions of the present invention may be prepared of such high viscosity and consistency that they form adhesive xe2x80x9cgluexe2x80x9d lines of thicknesses up to several hundred microns to lute less close fitting restorations, for example inlays prepared using present state-of-the-art CAD-CAM devices. Compositions of the invention are mechanically strong, abrasion resistant, and are esthetically suitable and serve as the sole structural element to retain inlay, crowns and bridges or other appliances to tooth structure.
Filling Compositions
A preferred dental treatment in accordance with the invention is the application of dental filling compositions which include a curing agent and at least one salt compound within the scope of general formula I. Preferably the dental filling composition includes finely divided reactive filler that can react ionically with the acids or acid derivatives of the monomer. Preferably the composition is applied to a tooth as a filling material using conventional techniques as a one-component material and is cured with application of visible light in conventional manner.
Pit and Fissure Sealants
In a preferred embodiment of the invention a one or two component pit and fissure sealant which includes at least one salt compound within the scope of general formula I is applied to anatomic defects and/or the exterior of teeth. The sealant limits the ability of caries-forming bacteria to colonize the pits, fissures and other surfaces of the teeth. Pit and fissure sealant compositions in accordance with the invention are an especially valuable means of reducing caries by filling and eliminating enamel defects. The pit and fissure sealants of the invention are preferably applied without prior acid etching or the use of rubber dam to teeth. In one embodiment fluoride eluting compounds and glasses are preferably included in compositions of the invention. Fluoride is eluted to reduce the incidence of caries in tooth substance adjacent the compositions of the invention.
In accordance with the method of the invention cement and restorative compositions include at least one polymerizable acid reactive ethylenically unsaturated compound within the scope of general formula I. Such compositions are applied to tooth without prior etching of the tooth.
Method for Measurement of Compressive Strength Using International Standard Organization(ISO) 9917:1991(E) at pages 5-7 Dental Water-based Cements
For each material to be tested, cylinders 4 mm diameter and 6 mm long were prepared by filling the mixed material into teflon molds and light curing from each end for 40 seconds using The MAX Lite. The cylinders were removed from the molds and stored in water at 37xc2x0 C. for 24 hours prior to testing. The force needed to load the specimens to breaking point was measured using a universal testing machine operating at a crosshead speed of 5 mm/min.
Method of Transverse Flexural Strength Using International Standard Organization(ISO)4049:1988(E) at pages 6-8 Resin-based Filling Materials
The uncured material was filled into a split Teflon(copyright) mold with internal dimensions 25 mmxc3x972 mmxc3x972 mm. The exposed faces were then covered with polyester foil and clamped between transparent plastic blocks. The material was light cured for a total of 120 seconds by moving a dental curing light evenly backwards and forwards along the mold with the wand of the light in contact with the plastic blocks. After curing, the hardened specimens were stored in water at 37xc2x0 C. for 24 hours. Before being tested, any remaining flash along the edges of the specimens was carefully removed and the exact dimensions of each specimen measured. The specimens were then tested in three point bending mode using a universal testing machine set to a crosshead speed of 0.75 mm/min, with the sample resting on supports 20 mm apart and being loaded at the mid point. The transverse bending strength was calculated from the standard formula in Megapascals (MPa).
Method for Measurement of Diametral Tensile Strength
Modified procedures of ADA Specification No. 9 and No. 27 were utilized for all materials tested. Split teflon molds with internal dimensions of 3 mmxc2x10.1 mm high and 6 mmxc2x10.1 mm diameter were used. Mylar film was placed at the bottom of the mold. After the mixed material was conveyed into the mold in excess, a second piece of mylar film was placed on top of the mold and pressed with a metal plate to squeeze out excess material. The plate was then removed with the mylar still in place on top of the material and each side was cured for one minute using The MAX Lite. After being stored in 37xc2x0 C. water for 24 hours, specimens were tested on an Instron device for measurement of diametral tensile strength rising a 10 mm/minute crosshead speed.
Measurement of Adhesion to Dentin: Bond Strength to Dentin
Extracted human teeth used for the shear bond strength test was treated in 1% sodium hypochlorite for 18 to 24 hours and stored in distilled water in a refrigerator at about 4xc2x0 C. until needed. The teeth were washed with water, mechanically sanded with 120/320/600 grit carborundum paper until a flat dentin surface was exposed.
The teeth were then individually prepared as follows. Each tooth was blown dry with compressed dry air to ensure the dentin surface was free from noticeable moisture. A small plastic straw with 3.7 mm inner diameter and 2 to 3 mm in length was filled with mixed material and seated on the dentin so as to form a post without pressure. The upper open end of the straw was covered with a thin film and cured with The MAX Lite for 40 seconds. The specimens were then stored in distilled water at 37xc2x0 C. for more than 24 hours. The teeth were then vertically mounted in a one inch phenolic ring using self curing polymethyl methacrylate resin to provide a base for testing with the post at right angles thereto. The mounted specimens were loaded in shear in an Instron device for measurement of adhesion of the post to dentin at 5 mm/minute crosshead speed. The load was applied parallel to the prepared tooth surface and at right angles to the post until fracture occurred. The shear bond strength was calculated.
Method of Fluoride Releasexe2x80x94Static Extraction
A 1 mm thick by 20 mm diameter chip of the material was cured for 1 minute on each side with the Max Lite. A tiny hole was drilled in the chip. The specimen was tied with a nylon thread, suspended in 10 ml deionized water in a plastic jar caped with a lid, and stored in 37xc2x0 C. oven for one week, or otherwise indicated. Water in each jar was decanted to a separate 30 ml plastic beaker. The specimen in the jar was washed in 1 ml deionized water, and the water rinse was added to the respective beaker. To the jar, 10 ml of fresh deionized water was added and put back in the 37xc2x0 C. oven for the next measurement. The solution was diluted with 11 ml Total Ionic Strength Adjustor Buffer (TISAB) solution and measured with fluoride electrodes.
This method is used to simulate what happens in the mouth over a long period of time. The water is changed weekly. The values are reported in ppm, in micrograms of fluoride per gram of sample, and in micrograms of fluoride per centimeter square of sample surface.
Having generally described the invention, a more complete understanding can be obtained with reference to certain specific examples, which are included for purposes of illustration only. It should be understood that the invention is not limited to the specific details of the Examples.